1. Field of the Invention
The invention relates generally to analyzing the azimuth of a magnetic head used in a magnetic media read/write device. A presently preferred embodiment of the invention relates to a magnetic disk having a predetermined recording pattern for measuring head azimuth in a disc drive mechanism. The invention also has application to measuring head azimuth of a rigid disk drive, tape machine, or drum.
2. Description Relative to the Prior Art
In magnetic data storage media, to ensure unambiguous recording and playback, a magnetic head must establish and maintain a fixed orientation relative to each record track. A standrard orientation maintains a head centered transversely on a track and the head gap oriented at a 90-degree angle relative to the direction of the track. The angular orientation is known as head azimuth.
The widespread use of small computers, accompanied by both integral and separate disk drive mechanisms, has placed increasing numbers of magnetic storage devices in relatively unprotected environments. The relative vulnerability to mechanical damage of an inexpensive disk drive mechanism associated with a home and/or office small computer is significant, as compared with a data storage device associated with a large main frame computer installation.
A fundamental function of a floppy disk data storage system is the interfacing of data from different sources on different computers. In order to accomplish data transfer between computers, it is necessary that a head of a disk drive mechanism be oriented to a common standard.
A magnetic head used in playback of data should be oriented with the same azimuth as a magnetic head used for recording that data. If, for example, a slight change occurs in the azimuth of a head of a disk drive mechanism, that change will not affect the ability of the drive mechanism to reliably read data it recorded after the azimuth change occurred. The same disk drive mechanism (or a different disk drive mechanism) may not be able to read data, however, recorded before the change in azimuth occurred, because of the playback signal loss which occurs when there is a difference between recording and playback azimuths.
While many methods of measuring head azimuth are possible, a common practice with respect to a floppy disk drive mechanism has been to record signal bursts by a control head at various azimuth settings. The corresponding playback burst having the greatest amplitude is indicative of the head azimuth of a drive mechanism being analyzed. A disadvantage of this practice is the need for azimuth adjustments of the control head. Furthermore, the azimuth of the head being tested can merely be categorized, according to the azimuth settings selected for the control head.